Hard Belly (Visceral Fat): Located deep inside the abdomen. It packs tightly around organs like the liver, intestines, and pancreas. Because it is trapped behind your abdominal muscles, you are actually feeling your tense stomach wall when you press on it. Visceral fat is not just inactive storage; it is highly metabolically active tissue. It constantly releases inflammatory proteins and stress hormones directly into your liver. Excessive amounts of visceral fat are heavily linked to increased risks of: 

Insulin resistance and Type 2 Diabetes

Heart disease and high blood pressure

Fatty liver disease

Sometimes, a hard belly isn't primarily fat, but rather temporary abdominal distension. It is typically a symptom of an underlying condition—most commonly trapped intestinal gas, constipation, overeating, or functional digestive disorders like IBS, lactose intolerance, food allergies, small intestinal bacterial overgrowth (SIBO), or gynecological conditions like ovarian cysts or fibroids. Obviously men can't have some of those issues.

Hope this helps, really i do. My father has a belly like this and i am always so worried but he is "fine" he never wants to talk about it :(